Heat sterilizable elastic



Feb. 14, 1956 I DOYLE 2,734,503

HEAT STERILIZABLE ELASTIC FILM BACKED BANDAGE Filed Aug. 9, 1952INVENTOR.

BY Jafn '17. (15% United States PatentO amen I-IEAT- S TERILIZ ABLEELASTIC NDAG .2 m D Pseri ld, i l-i stt eq t Th K ndall i' n Boston, Msai a w rarsn e 9 M chusetts Application August 1952 Ser al 3 9?;52

12 Claims. (Cl. 128- 156) This invention is concerned with sterilizable,and sterilized, adhesive ready-to-apply bandages of the type comprisinga pad dressing and an adhesive backing strip. Theinvention is concernedparticularly with such bandsee ha lat l anno t d but" eas atta hable pymer c el i tast n Elastic bandages of the woven elastic thread type ofthe over-twist thread type have been utilized from time to time toprovide bandages having elasticity of a' b b t e e b e ha e'b w 'tnsafiif fq v bea e o t r b k ne a be-s t he so n be ame dirty, wet andstained. The provision of a comparatively taw bandage n e si ile 9suited Whisk has an elastic character sufii ciently low modulus as to bealmost like a second shin has long been a goal of e r ea ba da e i dl'st B atles-e w th a c P a fi m b ing ul ap a t amide e answer which theindustry was seel ting. Unfortunately,

hi her he e h h s o g n ifi9lti i iis a $99 2 fi ms a he ve anda es- Int e it at re dv ta adhesi nda e e u by e ood and rag mit et t6 i v a Wrp d nd Ste le Bse us h the means universally used jfor positive after ching te liza t i e able. f a ble t at sash po itive m ns be t ze in stili n e P a t e r a taapply bandages. llp until bandages ade inaccordance h t i n an' e imm r l; fi s er sterilized bandages werecommercially available because of no practical solution of inherentdifiiculties which reuse un i h l isto tis a id de ete ous ha ehem calhange suc banda e sinus anta in er.- Pa nts w teri iza n t m erat r Itis the object of this invention to proyide bandages comprising dressingmaterial adhered to elastically conformable but substantiallyundistorted polymeric film backed adhesive tapes having low modulus(within the range of from 1090 to 2400 pounds per square inch of crosssectional area) at 100% elongation, which after manufacture may besubjected to ordinary heat-sterilization temperatures withoutappreciable distortion or change in dimensions and withoutsubstantial'physicochemical deterioration.

The invention is illustrated in the accompanying drawings, n which: c

Figure l a plan view in perspective of a sterilized bandage inanenvelope, 1 i I Figure 2 is a plan view in perspective of a bandageafter removal ofthe wrapper,

Fig re 3 is a perspective view showing the. adhesive protective coveringbeing removed, and I Figure ,4 is a perspective .view showing thebandage applied over a knuckle. 7 Referring to Figures 1, 2,3 and 4,thewrapped sterilized bandage 10 indicates the condition of the bandagc'when received by a purchaser. After removal of the .wrapper or Vinyl'chlcride vi'nyl acetate copolymers 2,734,503 at nt d Feb.- 14; 9 6

an adherent pressure-sensitive adhesive 20, a superimposed adherent paddressing 2 2" and adhesive protective strips 24 nd 26; A turned backportion 28 of strip 26 fa ita remov of th s ps Ready-to apply'bandageshave as a common feature protective coverings for the pressure-sensitiveadhesive such as 24 and 26. These coverings which are generally ofcrinoline, or some other flexible sheet material relatively easilyseparated from the adhesive, are usually applied as a final step prior.to cutting individual bandages'from a web;

As has been indicated, one of the difiiculties which has confrontedelastic plastic bandage entrepreneurs has been unsightly distortion ofbandages by sterilization. I have discovered that the distortion inbandages brought about during heat-sterilization is due" to shrinkage ofthe film in one dimension (with accompanying slight expansion thereof inanother dimension) while the film is adherent to the protective covering'whi'ch lattershrinks either none at all or in a different degree ordirection. I have further discovered that 'such'heat-initiatedalterations in dimension are largely reversions approaching in degreethe changes from the original dimensions caused by'stretching the filmin themachine direction during processing. I have found that by adheringonly substantially unstretched or relaxed adhesive tape to theprotective covering, the distortion due to shrinkage inay be' eliminatedfor all practical purposes. i

A second 'difliculty which has confronted those who would provide h'eatsterilize d bandages having low modulus at elongation, has been thepractical attainment of sufiiciently low tensile-stress inbackingscapable of physically withstanding sterilization temperatures. 1 havediscovered that there exist three possibilities for such backings,having melting points above sterilization temperatures, namely: highmolecular weight internally;pla sticized polymeric films; highmolecular" weight pol mer films plasticized with molecular wcightpolymrsof the same monomer; and high molecular weight polymer filmsplasticizedwith polymers of othermon'oi ners. The employment ofnon-polymeric plasticizers (examples of which are given incolumn 4,lines 13 "to 2I)'universally used to reduce the modulus of elasticityincrdinary films must'be carefully limited, as hereinafter explained,when adhesives are used with films intended for bandages which are toundergo heat-sterilization. i

0f the internally plasticized group of possible backings I have foundthe following to be satisfactory to produce the elastioplastic filmbandages having low modulus at i099?) elongation, of this inventioni N-alkyl polyamides ,Chlo hated and chlorosulfonated polyethylenePolyamides containing oxo and thioxo linkages Of the group consisting ofhigh molecular weight polymers plasticizedwith low molecular weightpolymers of the same monomer, films of polymerized tetrafluorethyloneand polymerized trifiuoromonochloroethylene are examples of thosesuitable for the bandages of this invention. v v.

The third group, which I consider most suitable for bandage backingmaterials of this 'inventionfconsis'ts of high molecular weight polymersand c'opolyrne'rjs plasticized with polymeric plasticizers ofdifferentmonomers In group are:

than the polymer plasticized. Polymerized vinyl chloride polymerizedvinylidene chloride Polymerized vinyl fluoride Pol'ymerized vinylidenefluoride 'Yinyl' chloride-acrylonitrile copolymers Chlorinated p'olyrne'n'zed' "ethylene Vinyl chloride-vinylidene chloride copolymers Vinylchloride-vinyl acetate and vinylidene chloride terpolymers Vinylidenechloride-vinyl acetate copolymers Polyvinyl alcohol cross-linked withhexamethylene diisocyanate or other cross-linking agents Polyurethanessuch as that obtained by interaction of polyethylene glycols andhexamethyl diisocyanate and Elastic cellulose ethers In polymers ofmonomers including vinyl acetate, the latter should not be used inexcess of of the total monomer weight.

A third difficulty, which has not been fully appreciated by somemanufacturers of plastic adhesive tapes having higher moduluscharacteristics in plastic backings, has been the possibility ofphysico-chemical instability brought about by interdittusion andmigration of plasti cizers from and between the film and thepressure-sensitive adhesive. This problem has been known to exist evenunder ordinary storage conditions. Solutions have been proposed in thepast but the severe effects of heatsterilization upon physico-chemicalstability have not been encountered by any of the plastic tapes whichheretofore have been available such as those for plastic scaling, foranticorrosion wrappings and for electrical resistance wrappings. TheOace Patent No. 2,559,990 has proposed certain plasticizers forpolymeric-backed tapes containing predominately vinyl chloride but theproposed proportions of polymeric and non-polymeric plasticizersutilized are not satisfactory. for tapes having low modulus at 100%elongation which are to be subjected to sterilization temperatures. Ihave found that it is not enough to consider the plasticizer associatedwith the backing alone; the plasticizer in the pressure-sensitiveadhesive must be considered as well.

In accordance with this invention I have discovered that those tapeshaving the greatest degree of physicochemical stability are those inwhich both the backing and the adhesive are completely free ofnon-polymeric type plasticizers. Backings of the third group indicatedabove may be effectively plasticized to low modulus at 100% elongationsolely with from 25 to 40% based 011 the weight of the backing of one ofthe modified or unmodified polymerized condensation products of apolyhydric alcohol and a polybasic acid or with acrylonitrile rubbers.Examples of the former are the viscous alkyd resins which are mixturesof oil-modifiedpolyesters of sebacic acid and other polybasic acids soldunder the designation, Paraplex Resins, by the Resinous Products andChemical Company, Philadelphia, Pa. These resins may presently bepurchased in four molecular species by the designations 6-25, G-40, G-50and G-60. Other plasticizers in this general group are the polyglycolazelates sold under the trade name Plastolein 9715 and X-960-R by EmeryIndustries Inc., Cincinnati, Ohio, the polyethylene sebacate-azelatessold under the trade name Harflex 500 by the Hardesty Chemical Co. Inc.,New York, N. Y., and the polyesters sold by The General Electric Companyof Pittsfield, Mass., under the designations 2557 and 2559.

Of the group of acrylonitrile rubbers suitable as plasticizers, examplesare the butadiene-acrylonitrile copolymers sold under the trade name,Hycar, by the B. F. Goodrich Chemical Co., Cleveland, Ohio, and underthe trade name Paracril by the Naugatuck Division of the U. S. RubberCompany, New York, N. Y.

While plastic elastic adhesive tapes preferred for the bandages of thisinvention attain the greatest degree of physico-chemical stability whenonly polymeric plasticizers are used in both the adhesive and thebacking, I have obtained acceptable results when an amount ofnon-polymeric plasticizer not more than of the order of 3% of the totalweight of the backing and adhesive is utilized where the ratio betweenadhesive weight to the total weight varies from to 40%. Such smallamounts of non-polymeric plasticizer appear insutficient to materiallychange the optimum characteristics of the tape during or afterheat-sterilization. It is immaterial also whether this amount ofnon-polymeric plasticizer be utilized all in the plastic back, all inthe adhesive or divided. Very probably such non-polymeric plasticizersseek a balance eventually regardless of where they are initiallyplaced.-

Of the non-polymeric type plasticizers suitable for the tapes of thebandages of this invention to the extent of the order of 3% of theweight of the backing and adhesive, the following are examples:

Dioctyl phthalate Butyl benzoyl benzyl phthalate Dioctyl sebacateDi-Z-ethylhexyl adipate Ethylene diabietate Octyl diphenyl phosphateMethyl Cellosolve ricinoleate Trioctyl phosphate Opaque or filled filmbackings are preferred for the bandages of this invention buttransparent unfilled films with transparent or opaque adhesives areentirely satisfactory.

In general, fillers useful in rubber compounding may be used in thebackings of this invention with the possible exception of certainamphoteric and alkaline earth oxides, especially zinc oxide, whichappears to have some detrimental effect especially upon the vinylchloride and vinylidene chloride backings of this invention. Thepreferred filler for the backings in products of this invention istitanium dioxide. Other recommended fillers are hydrated silica,precipitated silica, alumina hydrate, calcium silicate, magnesiumsilicate, whiting and carbon black.

All of the vinyl chloride and vinylidene chloride polymers useful in theproducts of this invention should be stabilized by methods well known inthe vinyl film industry. Stabilizers which are useful for protectionagainst the deteriorating effects of heat and light are bariumricinoleate, cadmium ricinoleate, barium 2- ethylhexoate, cadmium2-ethylhexoate, dibutyl tin dilaurate, dibutyl tin maleate, dibutyl tinoxide, dibutyl di phenyl tin, bisglycidyl tin dilaurate, strontiumureate, strontium naphthenate, dioctyl pyrophosphate, polymerized alkylphenoxy epoxides, and glycidyl phenyl ether.

FILMS A preferred example of the films suitable for the products of thisinvention was prepared from a white polyvinyl chloride organosolmaterial in accordance with the following formula:

Example I Parts by weight An emulsion copolymer of vinyl chloride andvinyl acetate containing 93-95% vinyl chloride and having a particlesize of approximately 5-10 micr n A modified polymerized condensationproduct of The formula was ground in a water-jacketed pebble mill for 48hours to a point of adequate dispersion without substantial increase inviscosity.

Following deaeration and screening to remove undispersed pigment orresin particles, the organosol was metered in suitable wet thicknessonto a heavy supercalendered paper by means of an adjustable floatingknife of the type well known in the coating and spreading indnst'r'y.Thereafter it was passed through a multiple zoned oven increasing intemperature from approximately 125 F. to approximately 525 F. or to suchtemperatureas would permit adequate fusing or the polyvinyl chlorideresin. After fusing, the film was one which at room temperatureexhibited adequate physical charaeteristics' of tensile, elongation,modulus of elasticity, elastic recovery and tear resistance.

Another example of a preferred type of film was prepared from 'aflesh-colored organosol of polyvinyl chloride material in the samemanneras was used in preparing Example I but according to the followingformula:

Example II v Parts by weight An emulsion copolymer of vinyl chloride andvinylidene chloride where the vinyl chloride A further example of apreferred type of film was prepared from a white organosol from apolymer predominately vinylidene chloride in the same manner as was usedin preparing Example I from the following formula:

Example 111 Parts by weight PRIMERS Because of the relatively pooranchorage which hydrocarb'on adhesives achieve with some of the suitablebackings, particularly the vinyl chloride and vinylidene 5 chloridepolymer baokings, I prefer to utilize a primer to be applied to thebacking prior to application of the adhesive. As my preferred primer Iutilize the following:

Example I Parts by weight Latex (55% solids) of 60-65 parts monomericvinyl chloride polymerizedwith 40-35 parts butadien acrylonitrilecopolymer in 75:25 ratio 100 Latex (60% solids) of polymer of2-chlorobutadiene r Y r v r r 100 Dispersion of condensation products ofheptaldehyde and polyamines solids) 10 Methyl cellulose ether (1200cps.) 1

Other primers satisfactory for use with vinyl chloride and vinylidenechloride backings and hydrocarbon adhesives are:

Example 11 Parts by weight Latex (55% solids) of 60-65 parts monomericvinyl chloride polymerized with 40-35 parts butadiene-acrylonitrilecopolymer in 75.25 ratio--- 100 Natural rubber latex (centrifuged) 100Ammonium caseinate (added as solution) 1.7

films of this invention, the following are given:

Example 1 Parts by weight #1 pale crepe natural rubber 35 Dihydroabietic acid (tackifying resin) 15 Heat treated wood rosin (tackifyingresin) 15 Zinc oxide 28 Polyisobutylene 2 I Age resistors 3.5 Solvents,blended hydrocarbons 150 Example II Parts by weight Polyisobutylene(high molecular weight) 15 #1 thin pale crepe natural rubber 12 0Factice (White) -4 5 Glycerol ester of dihydroabietic acid (tackifyingIe Slll) Polyterpene resin (tackifying resin) 10 Dihydroabietic acid(tackifying resin) 5 Zinc oxide 25 Precipitated silica 3 Polyisobutylene(low molecular weight) 6 Age resistors l a 3.0 White lanolinfi 1Solvents, blended hydIQCafbOnS ..l 150 Example III Parts by weight GR-Srubber-X496-SP 56 Pale crepe rubber 16 Precipitated hydrated silica 11Age resistors 4.5 Synthetic beeswax 1.5 Titanium dioxide 8 Rosin, 40%polymerized 34.2 Hydrogenated rosin 34.2

butadiene 25 Morpholino abietate (10% aqueous solution) 5.0'Carboxymethyl cellulose .5

Example V Parts by weight Latex 50% solids) of a copolymerization ofmethylacrylate and butylacrylate in 1:1 ratio Hydroxyethyl cellulose .5

Example VI Latex 50% solids) of a copolymerization in equal parts ofvinyl chloride, acrylonitrile and ethyl acrylate In addition to theabove primers, that illustrated in Example I of the Oace patent abovementioned or the primer claimed in claim 1 of the Hopkins Patent No.2,555,745 may be utilized.

ADHESIVES As examples of adhesives preferred for the adhesive Solvents,blended hydrocarbon 250 An example of a pressure-sensitive adhesivewhich may be applied directly to backings of vinyl chloride andvinylidene chloride is as follows:

7 Example IV Parts by weight Copolymer of methyl acrylate-ethyl acrylate50 Aryl toluene sulfonamide-formaldehyde polymer (tackifying resin)Terpene modified phenol formaldehyde polymer (tackifying resin) 10Polyhydric alcohol ester of maleic modified heatisomcrized wood rosin(tackifying resin) 1O Benzoylbenzyl phthalate 3 Modified polymerizedcondensation polymer of dicarboyxylic acid and polyhydric alcohol l2Precipitated silica 8 Alkylated polyhydroxyphenol 3 Mixed solvents:(xylol-80%; propanol--10%;

methylisobutyl ketone10%) 150 The above adhesives are prepared bymilling the clastomers on a chilled mill for fifteen minutes, adding thetackifying resins while heating to 220-225 F. The mix is thentransferred to a suitable internal mixing device such as theBaker-Perkins mixer where the remaining ingredients, with the exceptionof the solvent, are added and the whole mixed for fifteen minutes at220225 F. Thereafter cooling water is circulated through the mixerjacket. The solvent blend is added slowly so as to avoid excessive lossby evaporation. When the solvent addition has been completed, theadhesive is ready for spreading.

The pad dressings of this invention may be of any conventional type ormaterial capable of withstanding sterilization temperatures. They may beabsorbent or nonabsorbent, woven or non-woven, fibrous or non-fibrous.Such diverse materials as cotton gauze, synthetic fiber gauzes, felts ofcotton, wool and synthetic fibers, sponges such as rubber and syntheticpolymer sponges, and algenic sponges, felts and fibrous pads arerepresentative and suitable.

The following general procedure may be employed in producing the novelbandages of this invention:

The plastic film-forming material is spread either in the form of asolution, a plastisol, an organosol or a latex onto a heavysuper-calendered paper of the type generally used for preparing castfilms. The film is then dried and fused (if necesary) while adherent tothe paper. If a primer anchorcoat is desired, the film is run through areverse roll spreader where it is coated with a skim coating of asuitable primer. The primer is dried either by pasage through a shortoven or by other conventional means. An adhesive, as previouslydescribed, is then applied to the backing in proper thickness by asuitable knife or reverse roll spreader. The combination then passesthrough an oven wherein the adhesive is dried. Upon emerging from thisoven, the tape and the adherent paper are slit, as a unit, into widthscorresponding to the lengths of the finished bandages. Each of thenarrow widths is then led to a machine similar to that described in theEustis Patent No. 2,029,260 wherein dressing materials are spotted ontothe adhesive surface and the divided crinoline or other covering stripsare applied with the fold-over running lengthwise. At this point thepaper carrier-surface is separated from the bandage material, the papercarrier being used to intermittently pull projecting portions of thebandage material out beneath a cut-off knife which severs the bandagestrip into successive individual bandages by cutting through the entirebandage strip including the crinoline coverings. The bandages are thenwrapped and packaged after which they are heatsterilized.

I claim:

1. A stable heat-resistantready-to-apply bandage comprising asubstantially unstretched, relaxed, polymeric film backing having a lowmodulus at elongation, a layer of pressure-sensitive adhesive and anadherent pad dressing, said backing and adhesive together containing atotal of not more than the order of 3% by weight of non-polymericplasticizer for said backing.

2. A bandage as claimed in claim 1 wherein the band age isheat-sterilizable.

3. A bandage as claimed in claim 1 wherein the adhesive is ahydrocarbon-elastomer pressure-sensitive adhesive.

4. A bandage as claimed in claim 1 wherein the adhesive is a polymericacrylic elastomer pressure-sensitive adhesive.

5. A bandage as claimed in claim 1 wherein the polymeric film backingincludes an internally plasticized polymer.

6. A bandageas claimed in claim 1 wherein the polymeric film backingincludes a polymer plasticized by a polymer of different monomericorigin.

7. A bandage as claimed in claim 1 wherein the polymeric film backingincludes a polymer plasticized by a lower molecular weight polymer ofthe same monomeric origin.

8. A bandage as claimed in claim 1 wherein the polymeric film backingincludes a polymer plasticized by a polymer of different monomericorigin derived from a condensation product of a polyhydric alcohol and apolybasic acid.

9. A bandage as claimed in claim 1 wherein the polymeric film backingincludes a polymer of monomers including a major proportion of vinylchloride plasticized by a polymer of different monomeric origin.

10. A bandage as claimed in claim 1 wherein the polymeric film backingincludes a polymer of monomers including a major proportion ofvinylidene chloride, plasticized by a polymer of difierent monomericorigin.

11. A bandage as claimed in claim 1 wherein the polymeric film backingand the layer of pressure-sensitive adhesive constitute a transparency.

12. A bandage as claimed in claim 1 wherein the polymeric film backingincludes a polymer of monomers including a major proportion of vinylchloride plasticized with 25 to 40% of the total weight of the backingof a polymeric plasticizer derived from a condensation product of apolyhydric alcohol and a polybasic acid.

References Cited in the file of this patent UNITED STATES PATENTS2,029,260 Eustis et al. Jan. 28, 1936 2,484,045 Morgan Oct. 11, 19492,644,804 Rubin July 7, 1953 2,656,331 Sprung Oct. 20, 1953

1. A STABLE HEAT-RESISTANT READY-TO-APPLY BANDAGE COMPRISING ASUBSTANTIALLY UNSTRETCHED, RELAXED, POLYMERIC FILM BACKING HAVING A LOWMODULUS AT 100% ELONGATION, A LAYER OF PRESSURE-SENSITIVE ADHESIVE ANDAN ADHERENT PAD DRESSING, SAID BACKING AND ADHESIVE TOGETHER CONTAINING